Convert between binary, decimal, hex & octal
Type a number into any field — decimal, hexadecimal, octal or binary — and the other three update instantly. It’s built for programmers working with colour codes, permissions, bit masks, memory addresses and low-level data. It uses your browser’s BigInt, so even very large values convert exactly with no rounding errors, and everything runs locally.
Frequently Asked Questions
What number bases does it support?
Binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16) — the four bases programmers use most. Hex isn’t case-sensitive, so ff and FF both work.
Does it handle very large numbers?
Yes. It uses BigInt, so large values (like 64-bit addresses) convert precisely — no loss of accuracy that ordinary JavaScript numbers would introduce beyond about 16 digits.
Why is a field turning red?
The value has a character that isn’t valid for that base — for example a 2 in a binary field, or a g in a hex field. Fix the digit and it’ll convert again.
Is my data private?
Yes — all conversion happens in your browser. Nothing is uploaded, logged or stored.
